The underground utility construction industry may involve directional drilling during which many obstacles may be encountered. Whether the obstacles are manmade or developed by soil conditions or earth formations, the challenges of completing a utility bore may be difficult to overcome, leading to loss of conduit, tools, or abandoning of the project altogether. Furthermore, environmental concerns and regulations may pose significant challenges to directional drilling operations which use methods currently available in the industry.
Directional drilling operations may encounter various challenges, some of which man made, while others naturally occurring. For example, creeks, rivers, ocean approaches, wetlands, deep valleys, and many other terrain conditions may pose challenges to conventional directional drilling and utility conduit pull-type operation, as such terrain may present difficult soil conditions. Often, when directional drilling into the surrounding soils, a driller may encounter rock, cobbles, shot rock, and fill, that may cause a utility conduit pull operation to become extremely difficult.
Various sizes of directional drills may be used to install underground utilities, however there are many disadvantages to the methods currently known. Conventional directional drilling methods typically involve using a back reamer with a swivel joint to enlarge the pilot bore hole defined by the drill string. Back reamers are cutting tools having a large mass with multiple cutting teeth and are typically selected to be one and a half times larger than the size of the desired bore hole. The conduit to be installed is typically attached to the swivel joint of a the back reamer and pulled back through the bore hole behind the back reamer. Conduits, such as high density polyurethane (HDPE) pipes or steel pipes, may become stuck, may break or be pulled until critical damage to the conduit occurs, rending the utility and the conduit path likely unusable. In addition, loss of down-hole tools, which are often very expensive, may occur, leading to significant costs in recovering and/or repairing such tools. The swivel can cause a space between the back reamer and conduit, in which debris may fall into the path of the conduits being pulled thus leading to damage of the conduit or to the conduit becoming stuck in the bore hole
In addition, back reaming may also lead to large voids under transportation surfaces, which may produce swells or large bumps in a traveled surface. Furthermore, the drilling system may hydra-lock causing drilling fluid to frack out. Fracking has become a concern, particularly when occurring near water ways or other protected environmental sites, and voluminous regulation is being put in place to limit or eliminate fracking in certain geographical areas.